1. Field of the Invention
The present invention relates to an electroluminescent display device which includes a plurality of electroluminescent elements arranged as a matrix.
2. Description of Related Art
Conventional electroluminescent display devices include a plurality of scan electrodes and data electrodes arranged as a matrix. These display devices perform matrix display by sequentially applying scan voltage to the plurality of scan electrodes and by applying actuating and deactuating display voltages to data electrodes to light up and put out EL (electroluminescent) elements provided at intersections of the scan electrodes with the data electrodes.
It must be noted here that EL elements are capacitive elements and so, electric charge stored by the EL elements during display along a scan electrode must be released before the display along the next scan electrode. However, if the electric charge of the EL elements is discharged for every scan electrode, then there will be a need for more charging and discharging circuits which, in turn, results in increased energy consumption.
Accordingly, Japanese Patent Laid open Publication No. Hei-2-103590 proposes the curbing of energy consumption by maintaining the charge of the EL element by continuing the application of display voltage when the display data for the present and the next scanning operation are the same.
Moreover, one type of EL display device performs pulse width brightness control by adjusting the application period of the actuating voltage during the application of the scan voltage.
In this way, it might be considered plausible to perform brightness control with the device disclosed in the above-described JP-A Hei-2-103590. However, the device disclosed in the same reference performs the application of only actuating and deactuating voltages and so, it cannot perform brightness control.